Current US birth-care practice is the extensive use of synthetic oxytocin for induction and augmentation of uterine contractions, yet there has been scarce investigationof maternal social behaviour followingsynthetic oxytocin despite the known critical role of oxytocin in supporting positive mood and mothering. The ALSPAC database allows us a unique opportunity to explore relationships betweensynthetic oxytocin(and other measures of the birth experience), oxytocin receptor epigenetics, and postpartum mood, and mothering in a large population study with detailedobstetrical, social, and affective data. ALSPACallows us to study women who were exposed tolow intervention rates (e.g., 14%synthetic oxytocin induction/augmentation, 25% epidural anaesthesia, and 10% caesarean surgery).These data would not be feasible to collect in the US due to today's high intervention rates (e.g., 57% augmentation, 76% epidural anaesthesia, and 34% caesarean).Another potentially important global measure of the birth experience is thelevel of birth-care supporting the normal physiology of birth. This can be quantified by the Optimality Index score, which can be calculated from existing ALSPAC obstetrical data in 8000 women.

ALSPAC also offers the unique prospect of gaining knowledge of potential dosage effects of synthetic oxytocin, andoxytocin receptor epigenetics, in a matched case control of a subset of women, with and without postpartum depression. Depression and dysregulation of the oxytocin system has been found measuring oxytocin genetic variation, but epigenetic variation has not been investigated. A dosage effect from synthetic oxytocin on vole behaviour has been found in one of our team member's lab (Sue Carter). While the ALSPAC dataset currently reports incidence of synthetic oxytocin, we proposeaccessing a subset of participants' medical records to extract synthetic oxytocin dosage during labor and birth. A small feasibility project was conducted in 2010 to identify issues in the methodology of extracting dosage data from ALSPAC records.

An additional strength of utilizing ALSPAC is the elimination of population recruitment issues, thus saving time and fiscal resources. The design of this proposed pilot has been informed by prior publications on ALSPAC and mood disorders, particularly several on depression co-authored by members of our team (Jean Golding and John Davis).1-3

Findings from this grant proposal will inform design of a prospective study to determine whether vulnerable women show changes in OXTR epigenetics before and after differential birth experiences that also affect mood and mothering.